Re: [PATCH v2] mm: fix double page fault on arm64 if PTE_AF is cleared

[Matthew Wilcox]

On Fri, Sep 06, 2019 at 09:57:47PM +0800, Jia He wrote:
> +		if (!pte_young(vmf->orig_pte)) {
> +			entry = pte_mkyoung(vmf->orig_pte);
> +			if (ptep_set_access_flags(vmf->vma, vmf->address,
> +				vmf->pte, entry, 0))
> +				update_mmu_cache(vmf->vma, vmf->address,
> +						vmf->pte);
> +		}
> +

Oh, btw, why call update_mmu_cache() here?  All you've done is changed
the 'accessed' bit.  What is any architecture supposed to do in response
to this?